The present invention relates to a semiconductor device, and more particularly to a semiconductor memory device which generates a column address selecting signal and transfers data within a rise time period of the generated column address selecting signal.
The semiconductor memory device such as the random access memory generates a column address selecting signal on the basis of internal clock frequency, so that within a rise time period of the generated column address selecting signal, a data transfer is made between the semiconductor memory device and a host device such as CPU through a digit line selected by the generated column address selecting signal.
The rise time period of the generated column address selecting signal depends upon a pulse width of the column address selecting signal. The rise time period of the column address selecting signal will hereinafter be referred to as an active width.
In recent years, as the high speed performance of the CPU has been on the improvement, it has been on the requirement for increasing the operating frequency of the semiconductor memory device. If the semiconductor memory device operates depending upon a frequency of a clock signal, then it is possible that an operational margin of the active width of the column address selecting signal is made narrow.
The advanced semiconductor memory device takes another operational system such that the advanced semiconductor memory device operates so that the active width of the column address selecting signal is fixed independent from the frequency of the clock.
If, however, the advanced semiconductor memory device operates so that the active width of the high frequency column address selecting signal is fixed independent from the frequency of the clock, then it is possible in case that all of chips provided internally operate in the active width of the high frequency column address selecting signal, whereby it is possible that chips are defective which have been inoperable in the high frequency column address selecting signal for selection or evaluation on the chips.
In the above circumstances, it had been required to develop a novel semiconductor memory device free from the above problem.